One electrophotographic image-forming device known in the art is a tandem-type color laser printer provided with four photosensitive drums corresponding to the four colors yellow, magenta, cyan, and black employed by the color printer, and an endless belt confronting the four photosensitive drums. One example of this type of tandem color laser printer that has been proposed includes a storage member below the endless belt for collecting waste toner removed from the belt.
However, the storage member is difficult to service when disposed beneath the endless belt. To remedy this problem, another color laser printer was proposed in which the storage member is positioned on the same side as the photosensitive drums, instead of underneath the endless belt. This color laser printer also includes a process frame for retaining the photosensitive drums that can be moved in and out of the main casing of the printer, a belt cleaner for contacting the conveying belt and removing waste toner therefrom, and a lift for conveying the waste toner toward the storage member. The storage member is also retained in the process frame.
However, in the color laser printer having this construction, the belt cleaner must be pivoted to separate the belt cleaning roller in the belt cleaner from the conveying belt when removing the process frame from the main casing and when transferring toner images onto sheets P. Consequently, there is potential for waste toner to separate from and fall off the belt cleaning roller when the roller is separated from the conveying belt.
Further, the belt cleaner in the cleaning unit of the conventional printer described above has a complex structure for separating the belt cleaner from the conveying belt when the process frame is pulled out of the printer. Therefore, studies were conducted on a structure that provides a waste toner collection chamber and a lift on the process frame and fixes the belt cleaner to the transfer unit, and more specifically to the follow roller side of the transfer unit.
However, with this construction, the belt cleaner may move in response to movement by the follow roller during operations of the transfer unit. In such cases, toner may leak through the region in which the lift is coupled to the belt cleaner.